Omron C200HW-CORT21, Operation Manual

Page: 48 / 62

Receiving a user defined CAN message
Section 4-6
46
Receive Buffer
1
2 New message
3
4
5
6
7
8
9
10
11
12
13
14
15
Oldest message
IR n+3.03
During the I/O refresh, the messages stored since the last I/O refresh are
transferred to the PLC and IR n+3.03 is set to indicate that new user defined
CAN messages have been received. If no messages have been received
since the last I/O refresh, no data is transferred to the PLC and IR n+3.03 is
set to ‘0’.
The figure below shows the structure of the receive buffer. The
representation in the PLC memory after transferring the buffer to the PLC is
identical.
Receive buffer structure
word n Number of new messages
received since the last I/O
refresh [BCD] range: 0000 ~ 9999
word n+1 Identifier message 1 [hex] range: 0000h ~ 07FFh
word n+2 Data length range: 0000 ~ 0008
word n+3 Data byte 2 Data byte 1
word n+4
Data byte 4 Data byte 3
word n+5 Data byte 6 Data byte 5
word n+6 Data byte 8 Data byte 7
word n+7 Identifier message 2 [hex] range: 0000h ~ 07FFh
word n+8 Data length range: 0000 ~ 0008
word n+9 Data byte 2 Data byte 1
word n+10 Data byte 4 Data byte 3
word n+11 Data byte 6 Data byte 5
word n+12 Data byte 8 Data byte 7
word n+85 Identifier message 15 [hex] range: 0000 ~ 07FFh
word n+86 Data length range: 0000 ~ 0008
word n+87 Data byte 2 Data byte 1
word n+88 Data byte 4 Data byte 3
word n+89
Data byte 6 Data byte 5
word n+90 Data byte 8 Data byte 7
Word n in the buffer structure indicates how many new messages have been
received since the last time the buffer was transferred to the PLC. Word n will
not count any further than 9999 new messages. Of course, the count should
not go over 15 otherwise messages are shifted out of the buffer without being
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